The present invention relates to a turbocharger for supercharging an engine.
In order to supercharge an engine of a vehicle effectively, a turbocharging system has been provided in which two different turbochargers are incorporated. In this system, a small sized turbocharger only is driven in case of small amount of the exhaust gas from the engine and both turbochargers are driven in case of large amount of the exhaust gas. In light of the fact that a small turbine rotor has small inertia, there is improved responsiveness for low rotation speeds of the engine.
However, the employment of two different turbochargers increases the weight of the vehicle and the complexity of the piping around the engine.